No Out Put Signal from Part in Place sensor to PLC

[Clinton Van Der Byl 0]

I had an a Major Error Fault on my PLC  but managed to reset Fault.

im not getting output signals from part in place sensors to PLC.

the Servo On button is not activating

[BobLfoot 301]

Just to clarify -

1.  What flavor of AB PLC had the major error fault?

2.  Did you notice a fault error number or description when you reset it?

3.  So none of your sensors or inputs make it to the PLC when you look for them in software?

4.  Have you covered the basics and made sure you didn't lose a power supply or fuse on the input side?

5.  Are the part sensors and servo on button wired to the same Input card?

Sorry to ask so many questions , butyour request is wide open at this point and sounds like you need to do a little basic troubleshooting and let us know what you find.

[Clinton Van Der Byl 0]

Hello Admin

Thank you for your reply and the questions. 

Questions are good for the growth and expansion of knowledge for PLC.

We diagnosed the main problem on the PLC side. 

The PLC lost its Logix memory and we had to upload the backup and we were off and running at 16h30.

we are still troubleshooting as to why this happened..

Please can you advice what could have caused the memory loss.

We are suspecting a power spike.

thank you again for your support

 

 

[Joe E. 259]

Bob's first question is relevant here...

Normally, a power cycle isn't enough to dump the program. Newer models have super-caps while older ones have batteries. If the battery is dead, a power cycle that's "more than brief" will cause it to lose its program.

Other than that, the only times I've seen a PLC "randomly" lose its program is when there's a power supply problem. Either the rack-mount power supply is getting flaky, there's a lot of noise on the line, the chassis/backplane is getting flaky, etc. I've seen that mostly with SLC 500 systems (SLC 5/0x) but it can happen with other models too.

[pcmccartney1 141]

Various Allen-Bradley processors have different means of storing and retaining the program.  We'll need to know the specific controller model number to help further. 

[Joe E. 259]

Whatever is going on, connect to the PLC before resetting the fault next time so you can see the fault codes. That will help diagnose the actual issue.

[Clinton Van Der Byl 0]

Thank you Joe.

We Have a Variety of PLC's on site. We had to get the Panasonic Robot Agent on site with the software.

I requested the software from the Panasonic Robot Agent.

 

thankyou for the advise

[Joe E. 259]

Is it a Panasonic PLC? If it's an AB PLC, you'll need to contact your local AB distributor to buy the software, depending on which PLC it actually is.